For the Salted Caramel Buttercream:,The caramel (steps 1-3) can be made up to two weeks ahead of time. Complete the buttercream by following step 4 on the same day that you make the macaron shells!,1. Heat sugar on medium high heat. Stir constantly with a whisk as the sugar begins to melt. Once the sugar begins to boil, stop stirring, just swirl the pot a few times.,______,3. Stir in sea salt. Let it come to room temperature before using it to make the buttercream. You now have salted caramel! The caramel can be made ahead of time and stored in the refrigerator for up to 2 weeks. Let it come back to room temperature before using it with the buttercream.,4. When ready to make the buttercream, mix the salted caramel in a mixer for about 3-5 minutes - you will notice it becomes lighter in color. Mix in the remaining 1/2 cup of butter. Then add in powdered sugar and mix until fluffy, scraping the sides occasionally.,For the Macaron Shells:,1. In the bowl of a standing mixer with the whisk attachment, whip the eggs on medium high speed until foamy. Slowly add the granulated sugar and continue to beat until stiff peaks form, but do not over beat.,2. Sift almond meal, powdered sugar, and cocoa powder into a bowl. The cocoa powder is optional for color - if you don't want to use it, add 2 tablespoons of powdered sugar to replace it. Add this mixture into the meringue. Fold together using a spatula just until incorporated. Try not to use more than 50 strokes/folds.,3, Transfer the batter to a piping bag and pipe small rounds onto baking sheets prepared with silicone mats or parchment paper. Sprinkle some sea salt on top of each shell for decoration. Let the shells sit for 30-45 minutes for the surfaces to dry out a bit. Bake at 300°F for 15-20 minutes. Remove from the oven and allow to cool on the pans for a moment. Transfer shells to cooling rack once they are cool enough to touch.,4. Match shells up in size. Once cooled completely, pipe the buttercream onto the bottom of one cookie, and sandwich another on to of it, pushing the filling to the edges. Store in airtight container in the refrigerator. Enjoy!